The sedimentary record of the Sanshui Basin:Implication to the Late Cretaceous tectonic evolution in the northern margin of South China Sea

作     者：Zhe ZHANG Nianqiao FANG Zhen SUN Zhe ZHANG;Nianqiao FANG;Zhen SUN

作者机构：Key Laboratory of Ocean and Marginal Sea GeologyInnovation Academy of South China Sea Ecology and Environmental EngineeringSouth China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 511458China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)Guangzhou 511458China University of Chinese Academy of SciencesBeijing 100049China School of Ocean SciencesChina University of GeosciencesBeijing 100083China 

出 版 物：《Journal of Oceanology and Limnology》 (海洋湖沼学报（英文）)

年 卷 期：2023年第41卷第2期

页      面：532-549页

核心收录：

学科分类：0710[理学-生物学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 0707[理学-海洋科学] 

基　　金：Supported by the Guangdong Special Support Talent Team Program(No.2019BT02H594) the National Natural Science Foundation of China(Nos.41502100,U2244221)。 

主　　题：continental margin South China Sea Sanshui Basin Late Cretaceous tectonic transition 

摘      要：Whether the South China continental margin had shifted from active subduction to passive extension in the Late Cretaceous remains controversial.Located in the northernmost of the South China Sea continental margin,Sanshui Basin developed continuous stratigraphy from Lower Cretaceous to Eocene and provides precious outcrops to study the regional tectonic evolution during the Cretaceous.Therefore,we conducted field observations,petrology,clay mineralogy,geochemistry,and detrital zircon chronology analyses of sedimentary rocks from the Upper Cretaceous Sanshui Formation in Sanshui Basin.Results suggest that the Sanshui Basin is characterized as an intermoutane basin with multiple provenances,strong hydrodynamic environment,and proximal accumulation in the Late Cretaceous.An angular unconformity at the boundary between the Lower and Upper Cretaceous was observed in the basin.The sedimentary facies of the northern basin changed from lacustrine sedimentary environment in the Early Cretaceous to alluvial facies in the Late Cretaceous.The zircon U-Pb ages of granitic gravelly sandstone from Sanshui Formation prominently range from 100 Ma to 300 Ma,which is close to the deposition age of Sanshui Formation.The major and trace elements of the Late Cretaceous sedimentary samples show characteristics of active continental margin,and are different from the Paleogene rifting sequences.Hence,we propose that the northern South China Sea margin underwent an intense tectonic uplift at the turn of the Early and Late Cretaceous(around 100 Ma).Afterward,the northern South China Sea margin entered a wide extension stage in the Late Cretaceous(~100 to~80 Ma).This extensional phase is related to the back-arc extension in the active continental margin environment,which is different from the later passive rifting in the Cenozoic.The transition from active subduction to passive extension in the northern South China Sea may occur between the late Late Cretaceous and the Paleogene.